Comment by skrebbel
3 months ago
Random drive-by nitpick:
> From the beginning of the development, id had requested from djgpp engineers that their DPMI client would be able to run on djgpp's DPMI server but also Windows 95 DPMI server.
I'm pretty sure that "DJGPP engineers" is just one guy, DJ Delorie. DJGPP was always open source so I bet he got some contributors, but if the rest of this sentence is true that "id has requested from djgpp engineers", it just means they asked the maker of an open source tool they used to please add a feature. I wonder whether they paid him for it or whether DJ just hacked it all in at id's request for kicks. His "about me" page suggests he does contracting so might be the latter.
DJGPP was spectacularly good back in the day. I didn't appreciate at the time what a monumental effort it must have been to port the entire GCC toolchain and runtime to DOS/Windows. Hats off to DJ Delorie!
Back then, DJGPP was a much bigger group, and most of the Quake kudos go to Charles Sandmann, author of cwsdpmi, who worked directly with Id to help them optimize their code for our environment.
Thank you for this work. It was my first C compiler in 1998. Y'all helped me on the mailing list and you even replied to my e-mails! I was 11 and this was insane to me.
You're welcome!
1 reply →
Omg I’m totally starstruck now!
Purely out of curiosity, was that all a volunteer open source effort or was the entire DJGPP group acting as a consulting organization?
The DJGPP project and its contributors were 100% volunteer. I'm sure some of the contributors took advantage of their involvement to obtain consulting gigs on the side (I did ;) but DJGPP itself didn't involve any. The Quake work was a swap; we helped them with optimizing, and they helped us with near pointers. Win-win!
Just passing by to thank you. As many others have mentioned, DJGPP was pivotal for my life. I compiled my first C/Allegro games in DJGPP back in the mid/late 90s.
And here you are!!
+1 DJGPP/Allegro key life experience on my parents Windows machine, thankyou!
Amen to that!
I think I remember there was some communication between ID and Charles Sandmann about CWSDPMI, so even though it's worded a bit strange for an open source project there's probably some thruth in it?
Also a bit strange how the author is surprised about Quake running in a 'VM', apparently they don't really know about VM86 mode in x86 processors...
Is the author surprised by that, or did you just misread it? The only relevant quote on that page that I see is “It is impressive to see Quake run at full speed knowing that Windows 95 runs DOS executable in a virtual machine.”
He is perhaps surprised that it runs _at speed_ in the VM, not that it runs in the VM which he already knows about.
I mean VM86 is not really a VM in the modern sense of the word. And the author doesn't seem to know.
2 replies →
I think if you're relatively young is hard to know computing history. Its oddly older than one thinks, even concepts that are seen as new. Its sometimes interesting to see people learn about BBS's which flourished 40 years ago.
It's a bit surprising because this is the author of the DooM Black Book and they know the underpinnings pretty well.
However, the difference between a DOS VM under Windows 9x and a Windows command prompt and a w32 program started from DOS is all very esoteric and complicated (even Raymond Chen has been confused about implementation details at times).
DPMI clients don’t run in a VM, though. They’re just a normal task like any other task / process in Windows.
So... Win32 runs in virtual mode. In 2025, we don't think of that as a Virtual Machine, but it totally is. Hardware access is trapped by the CPU and processed by the OS/DPMI server.
2 replies →
Only if they never call DOS or the BIOS or execute a Real Mode Software Interrupt. When they do, they ask the DPMI server (which could be an OS like Windows 9x or CWSDPIM) to make the call on their behalf. In doing so, the DPMI server will temporarily enter into a VM86 Virtual Machine to do execute the Real Mode code being requested.
http://www.delorie.com/djgpp//doc/libc-2.02/libc_220.html
1 reply →
VM in this usage means Virtual Memory - i.e. with page tables enabled. Two "processes" can use the same memory addresses and they will point to different physical memory. In Real Address mode every program has to use different memory addresses. The VM86 mode lets you to have several Real Mode programs running, but using Virtual Memory.
4 replies →
Would love to see some interviews etc with DJ if he's up for it
Same. I only have experience from M.U.G.E.N fighting engine with respect to DJGPP.
I remember back in the day using DJGPP (DJ Delorie) with the Allegro library (Shawn Hargreaves), building little games that compiled and ran on Windows and other OSes, and being part of the community.
You can still play the little game I made in under 10K for the Allegro SizeHack competition in 2000: https://web.archive.org/web/20250118231553/https://www.oocit...
Back then I was also writing a bunch of articles on game development: https://www.flipcode.com/archives/Theory_Practice-Issue_00_I...
Anyone on HN was active around that time? :) Fun time to be hacking!
5 replies →
Completely off topic;
So I just took a look at DJ’s website and he has a college transcript there. Something looked interesting.
Apparently he passed a marksmanship PE course at the first year. Is that a thing in US? I don’t know, maybe its common and I have no idea. I’d love to have a marksmanship course while studying computer science though.
US colleges have a very open curriculum, where you have wide leeway in what classes you actually take, especially in the early years of study. If you're coming from more European-style universities, this is vastly different to the relatively rigid course set you'd take (with a few electives here and there).
MIT offers a Pirate Certificate: https://physicaleducationandwellness.mit.edu/about/pirate-ce...
I wouldn't be surprised if it's a pretty normal thing in a few countries or regions in the world. Marksmanship and archery are also olympic sports.
Yeah, in Russia even thought everything is decided for you once you've selected your major, PE classes still for you to choose. Competition to get in was crazy too, none of that "first come, first served" - swimming only accepted top N students, table tennis held a tournament style competition (I went there with two friends and I had to play against both of them).
US colleges still have far more options, though.
It would be an easy “A” for a lot of people in the US!
My college required its graduates to pass a minimal swimming test. Just enough swimming ability to give a potential rescuer some extra time to effect the rescue, rather than have us go straight to the bottom of the sea. We all took a test in the first week or so. Those who failed had to take a course and retake the test.
As a sibling poster mentions, US universities often have a very open curriculum. At my university, I got PE credit for classical fencing!
The marching band could also count for PE credit. I believe you could only get credit for one semester for it, and my university required two semesters of PE, so I gave fencing a try, having never fenced before.
I needed one PE credit to get a degree from my community college. My school didn't offer marksmanship, but I would imagine it would fit into PE, archery certainly would and there's synergy. I took Table Tennis to graduate. I don't think my engineering school where I got my BS required Physical Education though.
US colleges last one year longer, and the first year is more academically similar to the last year of high school in Europe.
It's definitely not common. My US university required 2 physical education classes, but only if you were under 30 and hadn't served in the military. They may have offered marksmanship, but I just took running and soccer (aka football). The classes were graded pass-fail and didn't even count for academic credit.
My high school had some marksmanship trophy's in their case dating back to the 70s. Responsible gun ownership was a real thing when a sizable portion of the male population were veterans.
We have myriad available "electives" that contribute towards our degrees. I have college credit for "bowling and billiards" and "canoeing and kayaking".
I took an 8-week, 1-credit badminton course to fulfill my PE requirements. I wouldn't be surprised to find a marksmanship course.
It was great indeed. DJGPP is how I learned to to program.